An object provided with a structure wherein a seal lip of a stationary side is slidably connected to a seal flange on a rotation side is used as a sealing device for preventing muddy water or the like infiltrating from an external part to a hub bearing of an automobile.
FIG. 3 illustrates a conventional example of this type of sealing device; in other words, it is provided with a sealing device main body 110 mounted on the inner circumference of an outer ring 101, which is a stationary side on a hub bearing 100 of an automobile, and a slinger 120, composed of a sleeve 121, fitted on the outer circumference of an inner ring 102, which is a rotation side on the hub bearing 100, and a seal flange 122, extending from one end thereof; wherein, a side lip 111 provided on the sealing device main body 110 slidably connected to the seal flange 122 of the slinger 120, is slidably connected on the seal flange 122 of the slinger 120, and a radial lip 112 provided on the sealing device main body 110, positioned on the inner circumference side of the side lip 111 is slidably connected to the outer circumference surface of the sleeve 121 of the slinger 120.
Furthermore, a pulsar ring 123, formed in a disc-shape with a rubbery elastic body mixed with a magnetic powder, wherein different circumferentially alternating magnetic poles are magnetized, is adhered integrally on the outer side surface of the flange 122 of the slinger 120, and a magnetic rotary encoder is configured by a magnetic sensor (not illustrated) being disposed on an outer side of the pulsar ring 123, facing the outer side surface thereof in the axial direction.
That is, a sealing device of this type prevents infiltration of muddy water or the like from an outer part A to a bearing inner part B, by the shaking action of the seal flange 122 which rotates integrally with the inner ring 102, in a slide part of the seal flange 122 of the slinger 120 and the side lip 111 of the sealing device main body 110. Furthermore, even if muddy water or the like slightly infiltrates an enclosed space C of the inner circumference side thereof from a connected slide part of the seal flange 122 and the side lip 111, these are sealed by the connected slide part of the sleeve 121 of the slinger 120 and the radial lip 112, and is returned to the outer circumference side of the side lip 111 by the shaking action of the seal flange 122.
Moreover, a sealing device of this type is provided with a labyrinth seal 130, which is a non-contact type seal wherein an outer diameter tubular part 113 and an outer diameter end of the seal flange 122 of the slinger 120 in the sealing device main body 110 are facing in a radial direction, on the outer side of the side lip 111, with the object of improving muddy water resistance by making it less likely for muddy water or the like from the outer part A to cover the side lip 111, even in harsh environments (for example, please see the following prior art documents).